U.S. patent number 7,129,303 [Application Number 10/416,359] was granted by the patent office on 2006-10-31 for method for producing homo- and co-polymers of ethylene.
This patent grant is currently assigned to Samsung Atofina Co., Ltd.. Invention is credited to Won-Young Kim, Weon Lee, Chun-Byung Yang.
United States Patent |
7,129,303 |
Yang , et al. |
October 31, 2006 |
Method for producing homo- and co-polymers of ethylene
Abstract
The present invention provides a method for producing homo- and
co-polymers of ethylene, or more particularly a method for
producing homo- and copolymers of ethylene in the presence of (a) a
solid titanium catalyst produced by preparing a magnesium solution
by contact-reacting a halogenated magnesium compound with an
alcohol; reacting thereto an ester compound having at least one
hydroxyl group and a silicon compound having at least one alkoxy
group; and adding a mixture of a titanium compound and a silicon
compound; (b) organometallic compounds of Group II or III of the
Periodic Table; and (c) an alkoxysilane compound and a haloalkne
compound. The catalyst for homo- and co-polymerization of ethylene,
produced according to the present invention, exhibits a high
activity and the polymers produced by the method of the present
invention using said catalyst have the advantages of exhibiting a
high bulk density and a narrow molecular weight distribution.
Inventors: |
Yang; Chun-Byung (Daejon,
KR), Kim; Won-Young (Daejon, KR), Lee;
Weon (Daejon, KR) |
Assignee: |
Samsung Atofina Co., Ltd.
(Chungnam, KR)
|
Family
ID: |
19698066 |
Appl.
No.: |
10/416,359 |
Filed: |
November 9, 2001 |
PCT
Filed: |
November 09, 2001 |
PCT No.: |
PCT/KR01/01903 |
371(c)(1),(2),(4) Date: |
October 27, 2003 |
PCT
Pub. No.: |
WO02/38624 |
PCT
Pub. Date: |
May 16, 2002 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20040063875 A1 |
Apr 1, 2004 |
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Foreign Application Priority Data
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Nov 9, 2000 [KR] |
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2000-66412 |
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Current U.S.
Class: |
526/128; 502/115;
502/127; 526/123.1; 502/126; 502/125; 502/120; 526/124.3;
526/125.1; 526/142; 526/348; 502/103 |
Current CPC
Class: |
C08F
10/00 (20130101); C08F 10/00 (20130101); C08F
4/6493 (20130101); C08F 10/00 (20130101); C08F
4/6565 (20130101); C08F 10/00 (20130101); C08F
4/6465 (20130101); C08F 110/02 (20130101); C08F
110/02 (20130101); C08F 2500/18 (20130101) |
Current International
Class: |
C08F
4/42 (20060101) |
Field of
Search: |
;526/123.1,128,125.1,124.3,142,348
;502/115,120,125,126,127,103 |
References Cited
[Referenced By]
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|
Primary Examiner: Choi; Ling-Sui
Attorney, Agent or Firm: Meyertons, Hood, Kivlin, Kowert
& Goetzel, P.C. Meyertons; Eric B.
Claims
The invention claimed is:
1. A method for producing homo- and co-polymers of ethylene,
comprising polymerization in the presence of: (a) a solid titanium
catalyst produced by the method comprising: (i) preparing a
magnesium compound solution by contact-reacting a halogenated
magnesium compound with an alcohol; (ii) reacting the magnesium
compound solution with electron donors, the electron donors
comprising an ester compound having at least one hydroxyl group and
a first silicon compound having at least one alkoxy group
represented by the general formula R.sub.nSi(OR).sub.4-n, wherein R
is a hydrocarbon having 1 12 carbons, and wherein n is an integer
from 0 3; and (iii) further reacting the mixture resulting from the
reaction of the magnesium compound solution with electron donors
with a titanium compound and a second silicon compound represented
by the general formula R.sub.nSiCl.sub.4-n, wherein R is hydrogen,
alkyl, alkoxy, haloalkyl, aryl group having 1 10 carbons,
halosilyl, or halosilylaklyl group having 1 8 carbons, and wherein
n is an integer from 0 3; (b) organometallic compounds of Group II
or III of the Periodic Table; and (c) an alkoxysilane compound and
a haloalkane compound.
2. The method of claim 1, wherein the ester compound having at
least one hydroxyl group is an unsaturated aliphatic acid ester
having at least one hydroxyl group, an aliphatic monoester or
polyester having at least one hydroxyl group, an aromatic ester
having at least one hydroxyl group, or an alicyclic ester having at
least one hydroxyl group.
3. The method of claim 1, wherein the titanium compound is
represented by a general formula of Ti(OR).sub.aX.sub.4-a, wherein
R comprises a hydrocarbon group, X comprises a halogen atom, and a
is a natural number of 0 4.
4. The method of claim 1, wherein said titanium compound is a
4-halogenated titanium, a 3-halogenated alkoxytitanium, a
2-halogenated alkoxytitanium, or a tetralkoxytitanium.
5. The method of claim 1, wherein the titanium compound is titanium
tetrachloride, and the second silicon compound is silicon
tetrachloride.
6. The method of claim 1, further comprising producing the solid
titanium catalyst by further reacting the product of step (a) (iii)
with an additional titanium compound.
7. The method of claim 1, wherein the alkoxysilane compound is
represented by a general formula of R.sub.nSi(OR).sub.4-n, wherein
R comprises a hydrocarbon having 1 20 carbons and n is an integer
from 0 to 3.
8. The method of claim 1, wherein the alkoxysilane compound is an
aromatic silane, an aliphatic silane, or a mixture thereof.
9. The method of claim 1, wherein the ester compound having at
least one hydroxyl group is 2-hydroxy ethylacrylate, 2-hydroxy
ethylmethacrylate, 2-hydroxy propyl acrylate, 2-hydroxy
propylmethacrylate, 4-hydroxy butylacrylate, pentaerythritol
tri-acrylate, 2-hydroxy ethyl acetate, methyl 3-hydroxy butylate,
ethyl 3-hydroxy butylate, methyl 2-hydroxy isobutylate, ethyl
2-hydroxy isobutylate, methyl-3-hydroxy-2-methyl propionate,
2,2-dimethyl-3-hydroxy propionate, ethyl-6-hydroxy hexanoate,
t-butyl-2-hydroxy isobutylate, diethyl-3-hydroxy glutarate,
ethyl-lactate, isopropyl lactate, butyl isobutyl lactate, isobutyl
lactate, ethyl mandelate, dimethyl ethyl tartrate, ethyl tartrate,
dibutyl tartrate, diethyl citrate, triethyl citrate,
ethyl-2-hydroxy-caproate, diethyl bis-(hydroxymethyl) malonate,
2-hydroxy ethyl benzoate, 2-hydroxy ethyl salicylate,
methyl-4-(hydroxy methyl)benzoate, methyl-4-hydroxy benzoate,
ethyl-3-hydroxy benzoate, 4-methyl salicylate, ethyl salicylate,
phenyl salicylate, propyl-4-hydroxy benzoate, phenyl 3-hydroxy
naphthanoate, monoethylene glycol monobenzoate, diethylene glycol
monobenzoate, triethylene glycol monobenzoate or hydroxy
butyl-lactone.
10. The method of claim 1, wherein the first silicon compound
having at least one alkoxy group is dimethyldimethoxysilane,
dimethyldiethoxysilane, diphenyldimethoxysilane,
methylphenyldimethoxysilane, diphenyldiethoxysilane,
ethyltrimethoxysilane, vinyltrimethoxysilane,
methyltrimethoxysilane, phenyltrimethoxysilane,
methyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane,
butyltriethoxysilane, phenyltriethoxysilane,
ethyltriisopropoxysilane, vinyltributoxysilane, ethylsilicate,
butylsilicate, or methyltriaryloxysilane.
11. The method of claim 1, wherein the titanium compound is
TiCl.sub.4, TiBr.sub.4, TiI.sub.4, Ti(OCH.sub.3)Cl.sub.3,
Ti(OC.sub.2H.sub.5)Cl.sub.3, Ti(OC.sub.2H.sub.5)Br.sub.3,
Ti(O(i-C.sub.4H.sub.9))Br.sub.3, Ti(OCH.sub.3).sub.2Cl.sub.2,
Ti(OC.sub.2H.sub.5).sub.2Cl.sub.2,
Ti(O(i-C.sub.4H.sub.9)).sub.2Cl.sub.2,
Ti(OC.sub.2H.sub.5).sub.2Br.sub.2, Ti(OCH.sub.3).sub.4,
Ti(OC.sub.2H.sub.5).sub.4, or Ti(OC.sub.4H.sub.9).sub.4.
12. The method of claim 1, wherein the second silicon compound is
silicon tetrachloride, a trichlorosilane, a trichlorosilane, or a
monochlorosilane.
13. The method of claim 1, wherein the second silicon compound is
methyltrichlorosilane, ethyltrichlorosilane,
phenyl-trichlorosilane, dimethyldichlorosilane,
diethyldichlorosilane, diphenyldichlorosilane,
methylphenyldichlorosilane, or trimethylchlorosilane.
14. The method of claim 1, wherein the haloalkane compound
comprises a compound having 1 20 carbon atoms and at least one
halogen.
15. The method of claim 1, wherein the alkoxysilane compound is
diphenyldimethoxysilane, phenyltrimethoxysilane,
phenylethyldimethoxysilane, phenylmethyldimethoxysilane,
isobutyltrimethoxysilane, diisobutyldimethoxysilane,
diisopropyldimethoxysilane, di-t-butyldimethoxysilane,
t-butyltrimethoxysilane, cyclohexylmethyldimethoxysilane,
dicyclopentyldimethoxysilane, dicyclohexyldimethoxysilane,
2-norbornan-triethoxysilane, 2-norbornan-methyldimethoxysilane,
vinyltriethoxysilane, or a mixture thereof.
16. The method of claim 1, wherein the haloalkane compound is
monochloromethane, dichloromethane, trichloromethane,
tetrachloromethane, monochloroethane, 1,2-dichloroethane,
monochloropropane, monochlorobutane, monochloro-secondary-butane,
monochloro-tertiary-butane, monochlorocyclohexane, chlorobenzene,
monobromomethane, monobromopropane, monobromobutane,
monoiodomethane, or a mixture thereof.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention provides a method for producing homo- and
co-polymers of ethylene, or more particularly a method for
producing homo- and copolymers of ethylene by using a catalyst with
high activity to produce said polymers with high bulk density and
narrow molecular weight distributions.
2. Description of the Related Art
Catalysts containing magnesium for polymerization or
copolymerization of ethylene are known to have very high catalytic
activities and to produce polymers with high bulk density and are
suitable for use in liquid phase or gas phase polymerizations.
Liquid phase polymerization of ethylene denotes a polymerization
process performed in a medium such as bulk ethylene, isopentane, or
hexane. Important characteristics of catalysts used in this process
include high catalytic activity, production of a reasonable bulk
density of the resultant polymers, etc. Of these characteristics,
catalytic activity is deemed to be the most important.
Many titanium-based catalysts containing magnesium for olefin
polymerization, and the manufacturing methods thereof have been
reported. Many processes that use magnesium solutions to produce
catalysts capable of generating olefin polymers with a high
apparent bulk density are known. A magnesium solution may be
obtained by reacting magnesium compounds with electron donors such
as alcohols, amines, cyclic ethers, or organic carboxylic acids in
the presence of a hydrocarbon solvent. The use of an alcohol as an
electron donor is disclosed in U.S. Pat. Nos. 4,330,649 and
5,106,807. Further, methods for the production of catalysts
containing magnesium by reacting a liquid-phase magnesium solution
with a halogenated compound such as titanium tetrachloride are well
known. Moreover, there have been attempts to control polymerization
activity or molecular weight distribution by adding ester
compounds. Such catalysts produce polymers with a high bulk
density; however, improvements can still be made with respect to
catalytic activity and molecular weight distribution of the
resulting polymers. Moreover, tetrahydrofuran, a cyclic ester, has
been used as a solvent for magnesium compounds in U.S. Pat. Nos.
4,477,639 and 4,518,706.
U.S. Pat. Nos. 4,847,227, 4,816,433, 4,829,037, 4,970,186, and
5,130,284 have reported the use of electron donors such as
dialkylphthalate, phthaloyl chloride, etc. in reactions with a
titanium chloride compound in the production of olefin
polymerization catalysts. These catalysts display superior
polymerization activity and are also capable of enhancing the bulk
density of the resulting polymers.
U.S. Pat. No. 5,459,116 teaches a method of production of a
titanium solid catalyst by contact-reacting a magnesium solution
containing an ester having at least one hydroxyl group as an
electron donor with a titanium compound. By this method, it is
possible to obtain a catalyst with high polymerization activity,
which also produces high bulk density to the resulting polymers;
however, there is still room for further improvement.
With respect to polymerization of .alpha.-olefins, particularly,
with respect to polymerization of propylene, the art of using
external electron donors for increasing stereo-regularity is
commonly known in the field and is widely used in the industry. As
for external electron donors, alkoxy silane compounds are widely
known. However, in these cases, the stereo-regularity of polymers
increases, but the molecular weight distribution broadens in
relative terms. Korean Patent Notification No. 93-665 discloses a
method of broadening the molecular weight distribution by using an
organic silane as an external electron donor during polymerization
of propylene, and the benefits thereof.
SUMMARY OF THE INVENTION
The objective of the present invention is to provide a method for
producing homo- and co-polymers of ethylene by using catalysts with
superior catalytic activity, wherein said polymers have high bulk
densities and narrow particle size distributions. More
particularly, the present invention provides a method for producing
homo- and copolymers of ethylene, having narrow molecular weight
distributions of polymers, which involves controlling the particle
morphology of polymers and using catalysts with high polymerization
activity.
Still other objectives and the utility of the present invention
will become apparent as references are made with respect to the
following descriptions and the claims thereto.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The method for producing homo- and co-polymers of ethylene
according to the present invention includes carrying out homo- or
co-polymerization of ethylene in the presence of the following: (a)
a solid complex titanium catalyst produced by a simple yet
efficient manufacturing process using magnesium, titanium, halogen,
and electron donors, which includes: (i) preparing a magnesium
solution by contact-reacting a halogenated magnesium compound with
an alcohol; (ii) reacting said solution with an ester compound
having at least one hydroxyl group and a silicone compound having
at least one alkoxy group; and (iii) adding a mixture of a titanium
compound and a silicon compound; (b) organometallic compounds of
Groups II or III of the Periodic Table; and (c) an alkoxysilane
compound and a haloalkane compound.
The types of halogenated magnesium compounds used for producing
catalysts used in the present invention include di-halogenated
magnesiums such as magnesium chloride, magnesium iodide, magnesium
fluoride, and magnesium bromide; alkymagnesium halides such as
methylmagnesium halide, ethylmagnesium halide, propylmagnesium
halide, butylmagnesium halide, isobutylmagnesium halide,
hexylmagnesium halide, and amylmagnesium halide; alkoxymagnesium
halides such as methoxymagnesium halide, ethoxymagensium halide,
isopropoxymagnesium halide, butoxymagnesium halide, octoxymagnesium
halide; and aryloxymagnesium halides such as phenoxymagnesium
halide and methyl-phenoxymagnesium halide. Of the magnesium
compounds described above, two or more compounds can be used in a
mixture. Further, the magnesium compounds described above can be
effectively used in the form of a complex compound with other
metals.
Of the compounds listed above, some can be represented by a simple
formula, but others cannot be so represented depending on the
production methods of the magnesium compounds. In the latter cases,
the magnesium compounds can generally be regarded as a mixture of
some of the listed compounds. For example, the following compounds
can be used in the present invention: compounds obtained by
reacting magnesium compounds with polysiloxane compounds, silane
compounds containing halogen, ester, or alcohol; and compounds
obtained by reacting magnesium metals with alcohol, phenol, or
ether in the presence of halosilane, phosphorus pentachloride, or
thionyl chloride. However, the preferable magnesium compounds are
magnesium halides, especially magnesium chloride or alkylmagnesium
chloride, preferably those having an alkyl group of 1 10 carbons;
alkoxymagnesium chlorides, preferably those having 1 10 carbons;
and aryloxymagnesium chlorides, preferably those having 6 20
carbons. The magnesium solution used in the present invention can
be produced by using the aforementioned magnesium compounds in the
presence a hydrocarbon solvent or in the absence thereof, in an
alcohol solvent.
The types of hydrocarbon solvents used in the present invention may
include aliphatic hydrocarbons such as pentane, hexane, heptane,
octane, decane, and kerosene; alicyclic hydrocarbons such as
cyclopentane, methylcyclopentane, cyclohexane, and
methylcyclohexane; aromatic hydrocarbons such as benzene, toluene,
xylene, ethylbenzene, cumene, and cymene; and halogenated
hydrocarbons such as dichloropropane, dichloroethylene,
trichloroethylene, carbon tetrachloride, and chlorobenzene.
To produce a magnesium solution containing a halogenated magnesium
compound, an alcohol is used as the solvent in the presence of one
or more of the aforementioned hydrocarbons or in the absence
thereof. The types of alcohol which may be used include those
containing 1 20 carbon atoms, such as methanol, ethanol, propanol,
butanol, pentanol, hexanol, octanol, decanol, dodecanol, octadecyl
alcohol, benzyl alcohol, phenylethyl alcohol, isopropyl benzyl
alcohol, and cumyl-alcohol, although an alcohol containing 1 12
carbon atoms is preferable. The average size of a target catalyst
and its particle distribution can vary according to the types and
content of alcohol, the types of magnesium compounds, the ratio of
magnesium to alcohol, etc. Nevertheless, the total amount of
alcohol required to produce the magnesium solution is at least 0.5
mole per mole of magnesium compound, preferably about 1.0 20 moles
per mole of magnesium compound, or more preferably about 2.0 10
moles per mole of magnesium compound.
During the production of the magnesium solution, the reaction of a
halogenated magnesium compound with an alcohol is preferably
carried out in the presence of a hydrocarbon medium. The reaction
temperature, while variable depending on the type and amount of
alcohol, is at least about -25.degree. C., preferably about 10
200.degree. C., or more preferably about 0 150.degree. C. It is
preferable to carry out the reaction for about 15 minutes to about
5 hours, preferably for about 30 minutes to about 4 hours.
Of the electron donors used in the production of catalysts used in
the present invention, the ester compounds having at least one
hydroxyl group include unsaturated aliphatic acid esters having at
least one hydroxyl group, such as 2-hydroxy ethylacrylate,
2-hydroxy ethylmethacrylate, 2-hydroxypropyl acrylate,
2-hydroxypropylmethacrylate, 4-hydroxy butylacrylate,
pentaerythritol triacrylate; aliphatic monoesters or polyesters
having at least one hydroxyl group, such as 2-hydroxy ethyl
acetate, methyl 3-hydroxy butylate, ethyl 3-hydroxy butylate,
methyl 2-hydroxy isobutylate, ethyl 2-hydroxy isobutylate,
methyl-3-hydroxy-2-methyl propionate, 2,2-dimethyl-3-hydroxy
propionate, ethyl-6-hydroxy hexanoate, t-butyl-2-hydroxy
isobutylate, diethyl-3-hydroxy glutarate, ethyl lactate, isopropyl
lactate, butyl isobutyl lactate, isobutyl lactate, ethyl mandelate,
dimethyl ethyl tartrate, ethyl tartrate, dibutyl tartrate, diethyl
citrate, triethyl citrate, ethyl-2-hydroxy-caproate, diethyl
bis-(hydroxy methyl) malonate; aromatic esters respectively having
at least one hydroxyl group, such as 2-hydroxy ethyl benzoate,
2-hydroxy ethyl salicylate, methyl-4-(hydroxy methyl)benzoate,
methyl 4-hydroxy benzoate, ethyl 3-hydroxy benzoate, 4-methyl
salicylate, ethyl salicylate, phenyl salicylate, propyl 4-hydroxy
benzoate, phenyl 3-hydroxy naphthanoate, monoethylene glycol
monobenzoate, diethylene glycol monobenzoate, triethylene glycol
monobenzoate; alicyclic esters having at least one hydroxyl group,
such as hydroxybutyl lactone, and others. The amount of the ester
compound having at least one hydroxyl group to be used should be
about 0.001 5 moles per mole of magnesium, or preferably about 0.01
2 moles per mole of magnesium.
The silicon compound having at least one alkoxy group can also be
used as another electron donor while producing catalysts used in
the present invention. A silicon compound represented by the
general formula R.sub.nSi(OR).sub.4-n (where R is a hydrocarbon
having 1 12 carbons and n is an integer from 0 to 3) is preferable.
In particular, the following compounds can be used:
dimethyldimethoxysilane, dimethyldiethoxysilane,
diphenyldimethoxysilane, methylphenylmethoxysilane,
diphenyldiethoxysilane, ethyltrimethoxysilane,
vinyltrimethoxysilane, methyltrimethoxysilane,
phenyltrimethoxysilane, methyltriethoxysilane,
ethyltriethoxysilane, vinyltriethoxysilane, butyltriethoxysilane,
phenyltriethoxysilane, ethyltriisopropoxysilane,
vinyltributoxysilane, ethylsilicate, butylsilicate,
methyltriaryloxysilane, etc. The amount of said compound is
preferably about 0.05 3 moles per mole of magnesium, or more
preferably about 0.1 2 moles per mole of magnesium. The temperature
for the contact-reaction of the magnesium solution, an ester
compound having at least one hydroxyl group, and an alkoxy silicone
compound may be about 0 100.degree. C., or more preferably about 10
70.degree. C.
To recrystalize the catalyst particles, the magnesium compound
solution reacted with the electron donor is reacted with a mixture
of a liquid titanium compound represented by the general formula of
Ti(OR).sub.aX.sub.4-a (where R is a hydrocarbon group, X is a
halogen atom, and a is a natural number from 0 to 4), and a
compound represented by the general formula of R.sub.nSiCl.sub.4-n
(where R is hydrogen, an alkyl, alkoxy, haloalkyl, or aryl group
having 1 10 carbons; or a halosilyl; or a halosilylalkyl group
having 1 8 carbons; and n is a natural number from 0 to 3).
The types of titanium compounds which satisfy the general formula
of Ti(OR).sub.aX.sub.4-a include a 4-halogenated titanium such as
TiCl.sub.4, TiBr.sub.4, and TiI.sub.4; a 3-halogenated
alkoxy-titanium such as Ti(OCH.sub.3)Cl.sub.3,
Ti(OC.sub.2H.sub.5)Cl.sub.3, Ti(OC.sub.2H.sub.5)Br.sub.3, and
Ti(O(i-C.sub.4H.sub.9))Br.sub.3; a 2-halogenated alkoxy-titanium
compound such as Ti(OCH.sub.3).sub.2Cl.sub.2,
Ti(OC.sub.2H.sub.5).sub.2Cl.sub.2,
Ti(O(i-C.sub.4H.sub.9)).sub.2Cl.sub.2, and
Ti(OC.sub.2H.sub.5).sub.2Br.sub.2; and a tetra-alkoxy titanium such
as Ti(OCH.sub.3).sub.4, Ti(OC.sub.2H.sub.5).sub.4, and
Ti(OC.sub.4H.sub.9).sub.4. A mixture of the above titanium
compounds can also be used in the present invention. However, the
preferable titanium compounds are those containing halogen, or more
preferably titanium tetrachloride.
The types of silicon compounds satisfying the above general formula
of R.sub.nSiCl.sub.4-n (where R is hydrogen, an alky, alkoxy,
haloalkyl, or aryl group having 1 10 carbons; or a halosilyl; or a
halosilylalkyl group having 1 8 carbons, and n is a natural number
from 0 to 3) include silicon tetrachloride; trichlorosilanes such
as methyltrichlorosilane, ethyltrichlorosilane,
phenyltrichlorosilane; dichlorosilanes such as
dimethyldichlorosilane, diethyldichlorosilane,
di-phenyldichlorosilane, and methylphenyldichlorosilane;
monochlorosilanes such as trimethylchlorosilane. A mixture of these
silicon compounds can also be used in the present invention, or
more preferably silicon tetrachloride can be used.
The amount of the mixture of a titanium compound and a silicon
compound used during re-crystallization of the magnesium compound
solution is about 0.1 200 moles per mole of magnesium compound,
preferably about 0.1 100 moles per mole of magnesium compound, or
more preferably about 0.2 80 moles per mole of magnesium compound.
The molar ratio of the silicon compound to the titanium compound in
the mixture is about 0.05 0.95, or more preferably about 0.1 0.8.
When the magnesium compound solution is reacted with the mixture of
a titanium compound and a silicon compound, the morphology and
particle sizes of the recrystallized solid constituents vary a
great deal according to the reaction conditions. Therefore, the
reaction of the magnesium compound solution with the mixture of a
titanium compound and a silicon compound should preferably be
carried out at a sufficiently low temperature to result in
formation of solid constituents. More preferably, the reaction
should be carried out by contact-reaction at about -70 70.degree.
C., or most preferably at about -50 50.degree. C. After the
contact-reaction, the temperature is slowly raised for about 0.5 5
hours to about 50 150.degree. C.
The solid catalyst particles obtained during the above process can
be further reacted with titanium compounds. These titanium
compounds are titanium halides or halogenated alkoxy titaniums with
an alkoxy functional group of 1 20 carbons. At times, a mixture of
these compounds can also be used. Of these compounds, however, a
titanium halide or a halogenated alkoxy titanium compound having an
alkoxy functional group of 1 8 carbons can be used, or more
preferably a titanium tetrahalide can be used.
The catalyst produced according to the process of the present
invention can be utilized for homo- or co-polymerization of
ethylene. In particular, the catalyst is used in
homo-polymerization of ethylene, and also in copolymerization of
ethylene and an .alpha.-olefin having three or more carbons such as
propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, or
1-hexene.
The polymerization reaction according to the present invention
involves producing homo- and co-polymers of ethylene in the
presence of the following:
(a) a solid complex titanium catalyst including magnesium,
titanium, halogen, and an electron donor;
(b) organometallic compounds of Groups II or III of the Periodic
Table; and
(c) an alkoxysilane compound and an haloalkane compound as
additives.
The solid titanium catalyst can be used as a component in the
polymerization reaction after pre-polymerization with ethylene or
an .alpha.-olefin. The pre-polymerization can be carried out with
the catalyst described above and an aluminum compound such as
triethylaluminum in a hydrocarbon solvent such as hexane at a
sufficiently low temperature or with ethylene or an .alpha.-olefin
under pressure. The pre-polymerization controls the morphology of
the catalyst particles by surrounding the catalyst particles with
polymer and is helpful in producing good-quality
post-polymerization morphology of the polymer product. The weight
ratio of polymer to catalyst after pre-polymerization is ordinarily
about 0.1:1 20:1.
The organometallic compound in the present invention can be
represented by the general formula of MR.sub.n, where M represents
a metal constituent of Group II or IIIA in the Periodic Table such
as magnesium, calcium, zinc, boron, aluminum, or gallium; R
represents an alkyl group with 1 20 carbons such as a methyl,
ethyl, butyl, hexyl, octyl, or decyl group; and n represents the
atomic valence of the metal constituent. Preferable organometallic
compounds include a trialkyl aluminum having an alkyl group of 1 6
carbons such as triethylaluminum and triisobutylaluminum, or a
mixture thereof can be utilized. On occasions, an organic aluminum
compound having one or more halogen or hydride groups such as
ethylaluminum dichloride, diethylaluminum chloride, ethylaluminum
sesquichloride, or diisobutylaluminum hydride can also be used.
In order to produce ethylene polymers with a narrow molecular
weight distribution and maintain very high catalytic activity, the
tertiary component additive should be an organic silicon compound
having alkoxy groups, or an alkoxysilane and haloalkane
compound.
The alkoxysilane compound can be represented by the general formula
of R.sub.nSi(OR).sub.4-n (where R is a hydrocarbon having 1 20
carbons and n is an integer from 0 to 3). In particular, the types
of alkoxysilane compounds which can be used include aromatic
silanes such as diphenyldimethoxysilane, phenyltrimethoxysilane,
phenylethyldimethoxysilane, and phenylmethyldimethoxysilane;
aliphatic silanes such as isobutyltrimethoxysilane,
diisobutyldimethoxysilane, diisopropyldimethoxysilane,
di-t-butyldimethoxysilane, t-butyltrimethoxysilane,
cyclohexylmethyldimethoxysilane, dicyclopentyldimethoxysilane,
dicyclohexyldimethoxysilane, 2-norbornan-triethoxysilane,
2-norbornan-methyldimethoxysilane, and vinyltriethoxysilane; and
mixtures thereof. In particular, among the aforementioned silane
compounds, a branched alkyldialkoxysilane such as
diisobutyldimethoxysilane and a cycloalkyldialkoxysilane such as
dicyclopentyldimethoxysilane were shown to be effective.
A haloalkane compound is a compound having 1 20 carbon atoms and at
least one halogen, or a mixture thereof can be used. Examples
include monochloromethane, dichloromethane, trichloromethane,
tetrachloromethane, monochloroethane, 1,2-dichloroethane,
monochloropropane, monochlorobutane, monochloro-secondary-butane,
monochloro-tertiary-butane, monochlorocyclohexane, chlorobenzene,
monobromomethane, monobromopropane, monobromobutane, and
monoiodomethane.
The polymerization reaction may be performed either in the gas
phase or as a bulk polymerization in the absence of an organic
solvent, or as a liquid slurry polymerization in the presence of an
organic solvent. These polymerization methods, however, are
performed in the absence of oxygen, water, and other compounds that
may act as catalytic poisons.
For liquid phase slurry polymerization, the concentration of the
solid complex titanium catalyst (a) in the polymerization reaction
system is approximately 0.001 5 mmol, in terms of titanium atoms in
the catalyst, per one liter of the solvent, or more preferably
approximately 0.001 0.5 mmol. Solvents that can be used include
alkanes such as pentane, hexane, heptane, n-octane, isooctane,
cyclohexane, and methylcyclohexane; alkylaromatics such as toluene,
xylene, ethylbenzene, isopropylbenzene, ethyltoluene,
n-propylbenzene, and diethylbenzene; halogenated aromatics such as
chlorobenzene, chloronaphthalene, and ortho-dichlorobenzene; and
mixtures thereof.
For gas phase polymerizations, the amount of the solid complex
titanium catalyst to be used (a) should be approximately 0.001 5
mmol, in terms of titanium atoms in the catalyst, per one liter of
the polymerization reactor, preferably approximately 0.001 1.0
mmol, or more preferably approximately 0.01 0.5 mmol.
The preferable concentration of the organometallic compound (b),
based on the organometallic atom, is about 1 2,000 moles per mole
of titanium atoms in catalyst (a), or more preferably about 5 500
moles.
To provide a high reaction rate of polymerization, the
polymerization is performed at a sufficiently high temperature
regardless of the polymerization process. Generally, a temperature
of approximately 20 200.degree. C. is appropriate, or more
preferably approximately 20 95.degree. C. The appropriate pressure
of monomers at the time of polymerization is about 1 atm to about
100 atm, or more preferably about 2 atm to about 50 atm.
The molecular weights of the polymers in the present invention are
described by the melt index (ASTM D 1238), as is generally known in
the art. The value of the melt index generally increases as the
molecular weight decreases. Moreover, polymer molecular weight
distributions were measured by gel permeation chromatography (GPC),
the method of which is generally known in the art.
The products obtained by the method of polymerization of the
present invention are solid ethylene homo-polymers or copolymers of
ethylene and an .alpha.-olefin and exhibit excellent bulk density
and fluidity. Since the yields of polymer are sufficiently high,
there is no need for the removal of catalyst residues.
EXAMPLES AND COMPARATIVE EXAMPLES
The present invention is further described by means of the examples
and comparative examples described below but should not be confined
or limited to these examples.
Example 1
Production of Catalyst
A solid complex titanium catalyst was produced by means of the
following three steps:
(i) Production of a Magnesium Compound Solution A 1.0 L reactor
equipped with a mechanical stirrer was purged with nitrogen
followed by the addition of 9.5 g of MgCl.sub.2 and 400 ml of
decane. After stirring at 500 rpm, 77 ml of 2-ethyl hexanol was
added to the reactor. The temperature was raised to 110.degree. C.,
and the reaction was allowed to continue for three hours. A
homogenous solution was obtained after the reaction and was cooled
to room temperature (25.degree. C.).
(ii) Contact-Reaction of the Magnesium Solution with an Ester
Containing a Hydroxyl Group and an Alkoxy Silane Compound 1.2 ml of
2-hydroxyethyl methacrylate and 14.0 ml of silicon tetraethoxide
were added to the cooled magnesium compound solution. The reaction
was allowed to continue for an hour.
(iii) Treating with a Mixture of a Titanium Compound and a Silicon
Compound After adjusting the temperature of the solution to room
temperature (25.degree. C.), a solution mixture of 50 ml of
titanium tetrachloride and 50 ml of silicon tetrachloride was
dripped into the reactor over the course of one hour. After
completing the dripping process, the temperature of the reactor was
raised to 80.degree. C. and maintained at that temperature for one
hour. After stirring, the mixture was cooled to room temperature.
The supernatant was removed and the remaining solid layer was mixed
with 200 ml of decane and 200 ml of titanium tetrachloride. The
temperature was raised to 100.degree. C. and maintained for two
hours. The mixture was then cooled to room temperature and was
washed with 400 ml of hexane to remove the free unreacted
TiCl.sub.4. The titanium content of the solid catalyst so produced
was 5.2 wt %. Polymerization
A 2-L high-pressure reactor was dried in an oven and assembled
while hot. In order to completely purge the reactor, the reactor
was filled with nitrogen and evacuated three times. The reactor was
filled with 1,000 ml of n-hexane, after which 1 mmol of
triethylaluminum, 0.1 mmol of cyclohexylmethyldimethoxysilane, 0.05
mmol of chloroform (CHCl.sub.3), and 0.03 mmol of the above solid
catalyst in terms of titanium atoms were added thereto. 500 ml of
hydrogen was then added. The temperature of the reactor was raised
to 80.degree. C. while stirring at 700 rpm. The pressure of
ethylene was adjusted to 80 psi, and the polymerization was allowed
to continue for an hour. After the polymerization, the temperature
of the reactor was lowered to room temperature and an excess of
ethanol was added to the reactor contents. The polymer thus
produced was collected by separation and was dried in a vacuum oven
at 50.degree. C. for at least six hours, whereby polyethylene was
obtained in the form of a white powder.
The polymerization activity (kg of polyethylene produced divided by
gram of catalyst) was calculated as the weight (kg) ratio of the
polymers produced to the amount of catalyst so used (gram of
catalyst). The results of the polymerization are shown in Table 1
along with the polymer bulk density (g/ml), melt index (g/10
minutes), and molecular weight distribution (Mw/Mn).
Examples 2 10
The polymerization was performed in the same manner as in Example 1
with the catalyst produced in Example 1 using various alkoxysilanes
and haloalkanes. The results of the polymerizations are shown in
Table 1.
Comparative Example 1
With the catalyst produced in Example 1, the polymerization was
carried out in the same manner as in Example 1, but without using
alkoxysilanes and haloalkanes during the polymerization process of
Example 1. The results are shown in Table 1.
Comparative Example 2
With the catalyst produced in Example 1, the polymerization was
carried out in the same manner as in Example 1, using alkoxysilanes
but without using haloalkanes during the polymerization process of
Example 1. The results are shown in Table 1
Comparative Example 3
With the catalyst produced in Example 1, the polymerization was
carried out in the same manner as in Example 1, using haloalkanes
but without using alkoxysilanes during the polymerization process
of Example 1. The results are shown in Table 1
TABLE-US-00001 TABLE 1 Alkoxysilane Molecular Compound Haloalkanes
Activity Bulk Weight Amount Amount (kg PE/g Density Distribution
Example Compound (mmol) Compound (mmol) of catalyst) (g/ml) (Mw/Mn)
1 A 0.1 CH-1 0.05 8.3 0.36 3.8 2 B 0.1 CH-1 0.05 8.7 0.37 3.9 3 C
0.1 CH-1 0.05 8.5 0.37 4.2 4 B 0.1 CH-2 0.3 8.4 0.36 4.0 5 B 0.1
CH-3 0.1 8.6 0.36 3.7 6 B 0.1 CH-4 0.1 8.7 0.36 3.9 7 B 0.1 CH-5
0.05 9.2 0.37 4.1 8 B 0.1 CH-6 0.05 8.3 0.36 3.8 9 C 0.05 CH-5 0.05
8.9 0.38 4.2 10 B 0.05 CH-1 0.05 9.0 0.38 4.0 CE 1 -- -- -- -- 6.0
0.36 6.7 CE 2 -- -- -- -- 7.1 0.36 4.1 CE 3 -- -- -- -- 4.8 0.35
6.5 *Types of alkoxysilanes - A: cyclohexyldimethoxysilane, B:
dicyclopentyldimethoxysilane, C: diisopropyldimethoxysilane; *Types
of haloalkanes - CH-1: chloroform, CH-2: ethylchloride, CH-3:
tertiarybutylchloride, CH-4: dichloromethane, CH-5:
cyclohexylchloride, CH-6: chlorobenzene; *CE: comparative
example.
As shown above, by way of the method for producing homo- and
co-polymers of ethylene according to the present invention, it is
possible to obtain homo- and co-polymers of ethylene, which have
high bulk density and narrow molecular weight distribution, with
high polymerization activity.
* * * * *